Distributed drainage basin water and sediment form dynamic process numerical simulation method and device

Abstract

The invention relates to the technical field of water and sediment power simulation, in particular to a distributed drainage basin water and sediment form power process numerical simulation method and device. A water-sand mixture continuous equation, a water-sand mixture motion equation, a sediment continuous equation and a riverbed deformation equation are solved simultaneously, a river channel water-sand form power module is developed, and then the river channel water-sand form power module is coupled with a preset land surface hydrological model and a preset slope sediment erosion model; a land hydrology-slope erosion-river channel water and sediment form dynamic process model is established, and then model calibration and verification are carried out by utilizing actually measured flow and sediment flux, so that the model is utilized to simulate a hydrology process, a slope erosion process and a river channel water and sediment form dynamic process of a watershed scale. Therefore, the problems of difficulty in adapting to calculation requirements of long-time and large-watershed scales, limitation in practical application and the like in the prior art are solved.

Description

Technical Field

[0001] This application relates to the field of hydrodynamic simulation technology, and in particular to a numerical simulation method and apparatus for distributed watershed hydrodynamic processes. Background Technology

[0002] Watershed sediment processes include slope sediment processes and channel sediment processes. Slope sediment processes involve hydrological processes such as rainfall, snow and glacier melting, surface runoff generation, soil infiltration, and slope runoff, accompanied by sediment production processes such as thin-layer runoff erosion and gully erosion. Channel sediment processes include inflow and outflow, sediment transport, deposition and scouring, and the evolution of riverbed morphology. These processes are highly coupled in time and space and are influenced by a combination of climate, topography, underlying surface conditions, and human activities, playing a vital role in regional ecological environment, river stability, and downstream socio-economic security.

[0003] In related technologies, watershed water and sediment process simulation methods can be divided into empirical methods and physical mechanism model methods. Empirical methods typically rely on soil and water conservation experimental observation data to establish statistical relationships between rainfall, runoff, and sediment, and can be extrapolated to larger areas, making calculations simple. Physical mechanism model methods, on the other hand, are based on the principles of water balance and sediment mass conservation, combined with dynamic equations to describe watershed water and sediment processes. Among these, the method of using distributed hydrological models combined with one-dimensional river network water and sediment models typically uses kinematic waves to approximate water flow confluence and combines empirical sediment transport formulas to simulate sediment transport, which can better reflect long-term runoff and erosion trends; the two-dimensional water and sediment morphological dynamic model of the entire watershed has greater physical consistency in describing sediment erosion, deposition, and morphological evolution within the river channel.

[0004] However, in related technologies, empirical methods lack descriptions of the physical mechanisms of water and sediment evolution, making it difficult to reveal the spatial differences and dynamic response characteristics of watershed water and sediment processes. This results in significant limitations when applied to complex terrain and climatic conditions. Furthermore, physical mechanism modeling methods require massive computations to accurately reflect the physical mechanisms of sediment erosion, deposition, and morphological evolution within river channels. Consequently, they are only suitable for simulating small-scale regional or flood events and are ill-suited for long-term, large-scale watershed computations. These issues urgently need to be addressed. Summary of the Invention

[0005] This application provides a distributed numerical simulation method and apparatus for water and sediment morphological dynamic processes in watersheds, in order to solve the problem that related technologies, in order to fit the physical mechanisms of sediment erosion, deposition and morphological evolution in river channels, involve huge computational loads, making it difficult to meet the computational needs of long time periods and large watershed scales, thus limiting their practical applications.

[0006] The first aspect of this application provides a numerical simulation method for distributed watershed water and sediment morphological dynamic processes, comprising the following steps: generalizing the river cross-section using a generalized geometric model of the river channel, simultaneously solving the continuity equation of the water-sediment mixture, the motion equation of the water-sediment mixture, the sediment continuity equation, and the riverbed deformation equation, to achieve coupled simulation of water and sediment transport, sediment scouring and deposition, and riverbed morphological evolution within the river network, and developing a river channel water and sediment morphological dynamic module; and integrating the river channel water and sediment morphological dynamic module with a preset land surface hydrological model and a preset slope sediment intrusion model. The land surface hydrology-slope erosion-channel water and sediment morphological dynamic process model is coupled with the erosion model to establish the model. Based on the model, the model is calibrated and verified using measured flow and sediment flux. After verification, the model is used to simulate the watershed-scale hydrological processes, slope erosion processes, and channel water and sediment morphological dynamic processes by inputting elevation, soil texture, vegetation cover type, and meteorological data.

[0007] Through the above technical means, the embodiments of this application can generalize the river cross section using a generalized geometric model, develop a river water and sediment morphology dynamic module, and then couple it with a preset land surface hydrological model and a preset slope sediment erosion model to establish a land surface hydrology-slope erosion-river water and sediment morphology dynamic process model. Then, the model is calibrated and verified using measured flow and sediment flux. Thus, the model is used to simulate the hydrological process, slope erosion process and river water and sediment morphology dynamic process at the watershed scale, realizing the numerical simulation of distributed watershed water and sediment dynamic processes. It not only conforms to the physical mechanisms of sediment erosion, deposition and morphological evolution in the river channel, but also uses a generalized geometric model of the river channel to adapt to complex river morphologies. On the slope, it uses the kinematic wave equation and the second sediment continuity equation to simplify the calculation process, adapting to the calculation needs of long time periods and large watershed scales, and taking into account both efficiency and practicality.

[0008] Optionally, in one embodiment of this application, the generalized geometric model of the river channel is used to generalize the river channel cross-section, so as to solve the continuous equation of the water-sediment mixture, the motion equation of the water-sediment mixture, the continuous equation of sediment, and the riverbed deformation equation simultaneously, so as to realize the coupled simulation of water and sediment transport, sediment scouring and deposition, and riverbed morphology evolution within the river network, and to develop a river channel water and sediment morphology dynamic module, including: generalizing the river channel cross-sectional morphology based on the topographic data of key river channels; and constructing a coupled simulation strategy for the one-dimensional river network water and sediment transport, sediment scouring and deposition, and riverbed deformation processes.

[0009] Through the above technical means, the embodiments of this application can simplify the amount of calculation in complex terrain by generalizing the cross-sectional morphology of the river channel, reduce the difficulty of practical application, and at the same time, by constructing a coupled simulation strategy, ensure that it fits the physical mechanisms of sediment erosion, siltation and morphological evolution in the river channel, thereby enhancing the reliability of practical application.

[0010] Optionally, in one embodiment of this application, the generalization of river cross-sectional morphology based on key river cross-sectional topographic data includes: selecting key river cross-sections within the river network and extracting cross-sectional elevation data based on the key cross-sections; calculating the vertical distance from the lowest point of the cross-section to a preset reference water surface based on the cross-sectional elevation data, and increasing it step by step according to a preset increasing strategy to obtain the cross-sectional water-passing area under different water depth conditions; and obtaining the average cross-sectional width-water depth relationship curve of the river segment based on the cross-sectional water-passing area under different water depth conditions.

[0011] Through the above technical means, the embodiments of this application can generate the average cross-sectional width-depth relationship curve of the river section based on the key cross-section of the river, and convert discrete terrain data into quantitative parameters. At the same time, the cross-sectional water flow area under different water depth conditions can be gradually increased by a preset addition strategy, which can cover different hydrological scenarios and enhance practical application capabilities.

[0012] Optionally, in one embodiment of this application, the coupled simulation strategy includes at least one of the following: a water-sediment mixture continuity equation, a water-sediment mixture motion equation, a first sediment continuity equation, and a riverbed deformation equation, wherein the water-sediment mixture continuity equation is: , The equation of motion for the water-sediment mixture is: , The first sediment continuity equation is: , The equation for riverbed deformation is: , in, t For time, x For spatial coordinates, A The cross-sectional area of ​​the water passage. Q For cross-sectional flow, E For sediment uplift flux. D For settling flux, B The width of the cross section. p For the porosity of the bed sand, q l The unit width lateral inflow rate, g It is the acceleration due to gravity. z b For riverbed elevation, h Because of the water depth, t b For the bed surface shear stress, r The density of the water-sediment mixture. r s The density of sediment particles, rw The density is that of pure water. c This represents the cross-sectional average sediment volume concentration. h c The water depth at the centroid of the cross-section. The density of the lateral incoming water flow. u l The lateral water flow velocity, s The sediment concentration in the lateral inflow water. A b This represents the cross-sectional area of ​​the riverbed.

[0013] Through the above technical means, the embodiments of this application can adopt a coupled simulation strategy to solve the limitations of the water-sediment uncoupled model based on the assumption of weak alluvial rivers, which cannot reflect the interaction between water flow, sediment and riverbed under strong unsteady flow conditions. By tracking the water and sediment morphology for a long time, the long-term dynamic process of water and sediment morphology is simulated. At the same time, a complete logical chain of runoff and sediment production, water and sediment transport and riverbed deformation is formed, which fits the physical mechanism of sediment erosion, siltation and morphological evolution in the river channel, and improves the ability to be applied in practice.

[0014] Optionally, in one embodiment of this application, coupling the riverbed water and sediment morphology dynamics module with a preset land surface hydrological model and a preset slope sediment erosion model to establish a land surface hydrology-slope erosion-riverbed water and sediment morphology dynamics process model includes: obtaining the runoff of the slope calculation grid; calculating the sediment erosion amount of the slope grid using the preset slope sediment erosion model based on the runoff; determining the confluence path from each slope grid to the river network based on the maximum slope of the slope grid and surrounding grids, and calculating the path length and slope; performing slope confluence calculation using the kinematic wave equation and the second sediment continuity equation to obtain the slope water and sediment confluence result; and inputting the slope water and sediment confluence result as lateral inflow and lateral sediment into the riverbed water and sediment morphology dynamics module.

[0015] Through the above technical means, the embodiments of this application can reconstruct the physical processes of runoff and sediment generation, water and sediment transport and accumulation in a watershed by observing the processes of slope runoff generation, slope erosion, slope confluence and river water and sediment transport. This can reflect the relationship between slope erosion and river siltation or scouring, adapt to complex terrain and climate conditions, and improve the applicability of practical applications.

[0016] Optionally, in one embodiment of this application, the motion wave equation and the second sediment continuity equation are respectively: , , , in, n The roughness coefficient is Manning's coefficient.R For hydraulic radius, S 0 represents the surface slope of the grid cell. R runoff This refers to the surface runoff within the grid calculated by the land surface hydrological model. R sed The amount of sediment produced within the grid calculated by the slope erosion model.

[0017] Through the above technical means, the embodiments of this application can use the kinematic wave equation and the second sediment continuity equation to calculate the slope confluence. On the one hand, the calculation can be simplified by the equation, which can improve the efficiency of slope water and sediment transport simulation. On the other hand, it can reflect the dynamic relationship between water flow and sediment, and ensure the continuity of the whole chain simulation of the land surface, slope, and river water and sediment morphology dynamic process, taking into account both efficiency and practicality.

[0018] The second aspect of this application provides a distributed watershed water and sediment morphological dynamics numerical simulation device, comprising: a development module for generalizing the river cross-section using a generalized river geometry model to simultaneously solve the water-sediment mixture continuity equation, the water-sediment mixture motion equation, the sediment continuity equation, and the riverbed deformation equation, thereby achieving coupled simulation of water and sediment transport, sediment erosion and deposition, and riverbed morphological evolution within the river network, and developing a river water and sediment morphological dynamics module; and a setup module for integrating the river water and sediment morphological dynamics module with a preset land surface hydrological model and a preset slope sediment erosion model. The model is coupled with a watershed model to establish a land surface hydrology-slope erosion-channel water and sediment morphological dynamic process model; the verification module is used to calibrate and verify the model based on the land surface hydrology-slope erosion-channel water and sediment morphological dynamic process model using measured flow and sediment flux; the simulation module is used, after verification, to simulate watershed-scale hydrological processes, slope erosion processes and channel water and sediment morphological dynamic processes by inputting elevation, soil texture, vegetation cover type and meteorological data, with the watershed as the object.

[0019] Through the above technical means, the embodiments of this application can generalize the river cross section using a generalized geometric model, develop a river water and sediment morphology dynamic module, and then couple it with a preset land surface hydrological model and a preset slope sediment erosion model to establish a land surface hydrology-slope erosion-river water and sediment morphology dynamic process model. Then, the model is calibrated and verified using measured flow and sediment flux. Thus, the model is used to simulate the hydrological process, slope erosion process and river water and sediment morphology dynamic process at the watershed scale, realizing the numerical simulation of distributed watershed water and sediment dynamic processes. It not only conforms to the physical mechanisms of sediment erosion, deposition and morphological evolution in the river channel, but also uses a generalized geometric model of the river channel to adapt to complex river morphologies. On the slope, it uses the kinematic wave equation and the second sediment continuity equation to simplify the calculation process, adapting to the calculation needs of long time periods and large watershed scales, and taking into account both efficiency and practicality.

[0020] Optionally, in one embodiment of this application, the development module includes: a generation unit for generalizing the river channel cross-sectional morphology based on the topographic data of key river channels; and a construction unit for constructing a coupled simulation strategy for one-dimensional river network water and sediment transport, sediment erosion and deposition, and riverbed deformation processes.

[0021] Through the above technical means, the embodiments of this application can simplify the amount of calculation in complex terrain by generalizing the cross-sectional morphology of the river channel, reduce the difficulty of practical application, and at the same time, by constructing a coupled simulation strategy, ensure that it fits the physical mechanisms of sediment erosion, siltation and morphological evolution in the river channel, thereby enhancing the reliability of practical application.

[0022] Optionally, in one embodiment of this application, the generation unit includes: a first generation subunit, used to select key river sections within the river network and extract section elevation data based on the key sections; a second generation subunit, used to calculate the vertical distance from the lowest point of the section to a preset reference water surface based on the section elevation data, and to increase it step by step according to a preset increasing strategy to obtain the cross-sectional water area under different water depth conditions; and a third generation subunit, used to obtain the average cross-sectional width-water depth relationship curve of the river segment based on the cross-sectional water area under the different water depth conditions.

[0023] Through the above technical means, the embodiments of this application can generate the average cross-sectional width-depth relationship curve of the river section based on the key cross-section of the river, and convert discrete terrain data into quantitative parameters. At the same time, the cross-sectional water flow area under different water depth conditions can be gradually increased by a preset addition strategy, which can cover different hydrological scenarios and enhance practical application capabilities.

[0024] Optionally, in one embodiment of this application, the coupled simulation strategy includes at least one of the following: a water-sediment mixture continuity equation, a water-sediment mixture motion equation, a first sediment continuity equation, and a riverbed deformation equation, wherein the water-sediment mixture continuity equation is: , The equation of motion for the water-sediment mixture is: , The first sediment continuity equation is: , The equation for riverbed deformation is: , in, t For time, x For spatial coordinates, A The cross-sectional area of ​​the water passage. Q For cross-sectional flow, E For sediment uplift flux.D For settling flux, B The width of the cross section. p For the porosity of the bed sand, q l The unit width lateral inflow rate, g It is the acceleration due to gravity. z b For riverbed elevation, h Because of the water depth, t b For the bed surface shear stress, r The density of the water-sediment mixture. r s The density of sediment particles, r w The density is that of pure water. c This represents the cross-sectional average sediment volume concentration. h c The water depth at the centroid of the cross-section. The density of the lateral incoming water flow. u l The lateral water flow velocity, s The sediment concentration in the lateral inflow water. A b This represents the cross-sectional area of ​​the riverbed.

[0025] Through the above technical means, the embodiments of this application can use a coupled simulation strategy to solve the limitations of the water-sediment uncoupled model based on the assumption of weak alluvial rivers, which cannot reflect the interaction between water flow, sediment and riverbed under strong unsteady flow conditions. It can simulate the long-term dynamic process of water and sediment morphology, and at the same time, form a complete logical chain of runoff and sediment production, water and sediment transport and riverbed deformation, which fits the physical mechanism of sediment erosion, siltation and morphological evolution in the river channel, and improves the ability to be applied in practice.

[0026] Optionally, in one embodiment of this application, the establishment module includes: a first calculation unit for obtaining the flow rate of the slope calculation grid; a second calculation unit for calculating the sediment erosion amount of the slope grid using the preset slope sediment erosion model based on the flow rate; a third calculation unit for determining the confluence path from each slope grid to the river network based on the maximum slope of the slope grid and the surrounding grids, and calculating the path length and slope; a fourth calculation unit for performing slope confluence calculation using the kinematic wave equation and the second sediment continuity equation to obtain the slope water and sediment confluence result; and an input unit for using the slope water and sediment confluence result as lateral inflow and lateral sediment inflow, and inputting the lateral inflow and lateral sediment inflow into the river channel water and sediment morphology dynamics module.

[0027] Through the above technical means, the embodiments of this application can reconstruct the physical processes of runoff and sediment generation, water and sediment transport and accumulation in a watershed by observing the processes of slope runoff generation, slope erosion, slope confluence and river water and sediment transport. This can reflect the relationship between slope erosion and river siltation or scouring, adapt to complex terrain and climate conditions, and improve the applicability of practical applications.

[0028] Optionally, in one embodiment of this application, the motion wave equation and the second sediment continuity equation are respectively: , , , in, n The roughness coefficient is Manning's coefficient. R For hydraulic radius, S 0 represents the surface slope of the grid cell. R runoff This refers to the surface runoff within the grid calculated by the land surface hydrological model. R sed The amount of sediment produced within the grid calculated by the slope erosion model.

[0029] Through the above technical means, the embodiments of this application can use the kinematic wave equation and the second sediment continuity equation to calculate the slope confluence. On the one hand, the calculation can be simplified by the equation, which can improve the efficiency of slope water and sediment transport simulation. On the other hand, it can reflect the dynamic relationship between water flow and sediment, and ensure the continuity of the whole chain simulation of the land surface, slope, and river water and sediment morphology dynamic process, taking into account both efficiency and practicality.

[0030] A third aspect of this application provides an electronic device, including: a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the program to implement the numerical simulation method for distributed watershed water and sediment morphological dynamic processes as described in the above embodiments.

[0031] A fourth aspect of this application provides a computer-readable storage medium storing a computer program that, when executed by a processor, implements the above-described numerical simulation method for distributed watershed water and sediment morphological dynamic processes.

[0032] The fifth aspect of this application provides a computer program product, including a computer program that, when executed, implements the above-described distributed watershed water and sediment morphological dynamic process numerical simulation method.

[0033] This application embodiment can use a generalized geometric model of the river channel to generalize the river channel cross-section, and simultaneously solve the continuity equation of the water-sediment mixture, the motion equation of the water-sediment mixture, the sediment continuity equation, and the riverbed deformation equation to develop a river channel water-sediment morphology and dynamics module. Then, the river channel water-sediment morphology and dynamics module is coupled with a preset land surface hydrological model and a preset slope sediment erosion model to establish a land surface hydrology-slope erosion-river channel water-sediment morphology and dynamics process model. Subsequently, the model is calibrated and verified using measured flow and sediment flux. Thus, the model is used to simulate the hydrological process, slope erosion process, and river channel water-sediment morphology and dynamics process at the watershed scale, realizing the numerical simulation of distributed watershed water-sediment dynamics processes. It not only conforms to the physical mechanisms of sediment erosion, deposition, and morphological evolution in the river channel, but also uses a generalized geometric model of the river channel to adapt to complex river channel morphologies. On the slope, it uses motion wave equations and a second sediment continuity equation to simplify the calculation process, adapting to the calculation needs of long time periods and large watershed scales, and taking into account both efficiency and practicality. This solves the problem that related technologies, in order to fit the physical mechanisms of sediment erosion, deposition, and morphological evolution in river channels, require a huge amount of computation, making them difficult to adapt to the computational needs of long periods and large watersheds, thus limiting their practical applications.

[0034] Additional aspects and advantages of this application will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of this application. Attached Figure Description

[0035] The above and / or additional aspects and advantages of this application will become apparent and readily understood from the following description of the embodiments taken in conjunction with the accompanying drawings, wherein: Figure 1 This is a flowchart of a numerical simulation method for distributed watershed water and sediment morphological dynamic processes provided in an embodiment of this application; Figure 2 This is a schematic diagram of three types of cross-sections obtained by generalizing a generalized geometric model of a river channel according to an embodiment of this application; Figure 3 This is a schematic diagram of a model for the formation of a land surface hydrology-slope erosion-channel water and sediment morphological dynamic process according to an embodiment of this application; Figure 4 This is a schematic diagram of the simulation results of the land surface hydrology-slope erosion-channel water and sediment morphology dynamic model of the Tuotuo River Basin according to an embodiment of this application; Figure 5 This is a schematic diagram of the hydrodynamic process of a key section according to an embodiment of this application; Figure 6 This is a block diagram of a distributed watershed water and sediment morphological dynamics numerical simulation device provided according to an embodiment of this application; Figure 7This is a schematic diagram of the structure of an electronic device provided according to an embodiment of this application.

[0036] Figure label: 60-Distributed watershed water and sediment morphological dynamics numerical simulation device; 100-Development module, 200-Establishment module, 300-Verification module, 400-Simulation module; 701-Memory, 702-Processor, 703-Communication interface. Detailed Implementation

[0037] The embodiments of this application are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain this application, and should not be construed as limiting this application.

[0038] The following describes a distributed numerical simulation method and apparatus for watershed morphological dynamics processes in watersheds, referring to the accompanying drawings. Addressing the issue mentioned in the background section that related technologies, while conforming to the physical mechanisms of sediment erosion, deposition, and morphological evolution within river channels, involve massive computational demands, making them unsuitable for long-term, large-scale watershed calculations and limiting their practical applications, this application provides a distributed numerical simulation method for watershed morphological dynamics processes in watersheds. In this method, a generalized geometric model of the river channel can be used to generalize the river cross-section, simultaneously solving the continuity equation of the water-sediment mixture, the motion equation of the water-sediment mixture, the sediment continuity equation, and the riverbed deformation equation. This develops a water-sediment morphological dynamics module, which is then integrated with a pre-set land surface hydrological model and a pre-set slope... A sediment erosion model is coupled to establish a land surface hydrology-slope erosion-channel water and sediment morphological dynamics model. Then, measured flow and sediment flux are used for model calibration and validation. The model simulates watershed-scale hydrological processes, slope erosion processes, and channel water and sediment morphological dynamics, achieving numerical simulation of distributed watershed water and sediment dynamics. This model not only closely reflects the physical mechanisms of sediment erosion, deposition, and morphological evolution within the channel but also utilizes a generalized channel geometry model to accommodate complex channel morphologies. On the slope, simplified calculations are achieved using kinematic wave equations and a second sediment continuity equation, adapting to the computational needs of long-term, large-scale watershed operations while balancing efficiency and practicality. This solves the problems of related technologies that, due to their inability to accurately reflect the physical mechanisms of sediment erosion, deposition, and morphological evolution within the channel, require massive computational resources, making them unsuitable for long-term, large-scale watershed operations and limiting their practical applications.

[0039] Before introducing the numerical simulation method for distributed watershed water and sediment dynamic processes provided in this application embodiment, a brief introduction to the research time, research location, and research data is given. This application embodiment selects the Tuotuo River Basin in the Yangtze River source area as a research example, with a research period of 1985-2018. The research data consists of runoff and sediment data provided by the Yangtze River Hydrological Bureau, precipitation-driven data provided by the China Meteorological Data Network, and other conventional meteorological observation data. The observation data may include, but is not limited to, wind speed at 2 m near the ground, maximum temperature, and minimum temperature.

[0040] The following provides a detailed description of a numerical simulation method for distributed watershed hydrodynamic processes provided in the embodiments of this application. Specifically, Figure 1 This is a flowchart of a numerical simulation method for distributed watershed water and sediment morphological dynamic processes provided in an embodiment of this application.

[0041] like Figure 1 As shown, the numerical simulation method for distributed watershed water and sediment dynamic processes includes the following steps: In step S101, the river cross section is generalized using a generalized geometric model of the river channel to solve the continuous equation of the water-sediment mixture, the motion equation of the water-sediment mixture, the continuous equation of sediment and the riverbed deformation equation simultaneously, so as to realize the coupled simulation of water and sediment transport, sediment scouring and deposition and riverbed morphology evolution in the river network, and develop the river channel water and sediment morphology dynamic module.

[0042] In the embodiments of this application, the generalized geometric model of a river channel refers to simplifying the irregular and complex cross-sectional morphology of a natural river channel (such as wandering rivers, distributary rivers, and other multi-channel river systems) into a regular geometric shape (U-shaped, V-shaped, Y-shaped, etc.) through mathematical methods. Figure 2 The processing method shown is as follows. Its purpose is to reduce the complexity of numerical calculations and facilitate equation solving while preserving the hydraulic characteristics of the river channel (such as flow capacity).

[0043] In addition, the river channel water and sediment morphology dynamics module can be understood as a numerical simulation module that simulates the coupling effects of water and sediment movement, sediment transport, and riverbed deformation processes based on a generalized river channel cross-sectional morphology.

[0044] In actual implementation, the embodiments of this application can simplify complex river cross sections through a generalized geometric model of the river channel, and then achieve coupled simulation of the water-sediment mixture continuity equation, water-sediment mixture motion equation, sediment continuity equation and riverbed deformation equation by solving the water-sediment transport, sediment scouring and deposition and riverbed morphology evolution process in the river network, so as to complete the development of the river channel water-sediment morphology dynamic module.

[0045] In some cases, embodiments of this application can utilize a large-scale land surface hydrological model, the Variable Infiltration Capacity model-glacier (VIC-glacier), and the Modified Universal Soil Loss Equation (MUSLE) to develop a river channel water and sediment morphology dynamic module. Furthermore, a set of governing equations consisting of the water-sediment mixture continuity equation, the water-sediment mixture movement equation, the sediment continuity equation, and the riverbed deformation equation can be combined with slope runoff and slope erosion results to calculate river channel water and sediment transport.

[0046] Specifically, in the embodiments of this application, the expression for calculating the sediment erosion of the slope grid using the MUSLE model can be, but is not limited to, as follows: , in, sed For sand production, a and b For the parameters to be calibrated, Q v Surface runoff, q p For the peak flow, K As a soil erodibility factor, C As a crop management factor, P For soil and water conservation measures, LS This is the slope length factor.

[0047] It is understood that the embodiments of this application can improve the applicability of the MUSLE model in high-altitude and cold regions by introducing a snow cover correction factor when snow cover is present on the slope. The snow cover correction factor is used to reduce the actual sediment yield under snow cover. The expression for calculating the sediment erosion of the slope grid using the MUSLE model in conjunction with the snow cover correction factor in the embodiments of this application can be, but is not limited to, as follows: , in, sad SNO represents the corrected sediment yield, and SNO represents the snow moisture content.

[0048] It should be noted that soil erodibility factors K The computation expression can be, but is not limited to, as: , in, S d The percentage of sand content. S i This represents the percentage of silt content. C i The percentage of clay content.C or This represents the percentage of organic carbon content.

[0049] In addition, topographic factors LS The computation expression can be, but is not limited to, as: , in, L slp For the slope length, m For the exponent term, f For slope, slp The grid slope (m / m) is expressed as an increase / decrease ratio. Since tillage and soil conservation measures are rarely implemented in the study area, the crop management and soil conservation measures factors are assumed to be constants in this embodiment.

[0050] Furthermore, the expression used in this application embodiment to calculate peak flow using the Soil and Water Assessment Tool (SWAT) can be, but is not limited to, the following: , in, α tc The proportion of daily precipitation. Area For the slope grid area, t conc This represents the convergence time of the grid.

[0051] Furthermore, in the embodiments of this application, the governing equations are solved using the following closed-form method: The expression for calculating the bed shear stress using Manning's formula in this application embodiment can be, but is not limited to, as follows: , in, t b For the bed surface shear stress, r For water density, g It is the acceleration due to gravity. A The cross-sectional area of ​​the water passage. n 0 represents the Manning roughness coefficient. u The cross-sectional average velocity is... R The radius is the hydraulic radius.

[0052] Furthermore, the expressions for calculating sediment uplift and settling fluxes in the embodiments of this application may be, but are not limited to, as follows: , in, E For sediment uplift flux. D This refers to the sediment deposition flux. oh For sediment settling speed, lThis is an empirical coefficient. h b The thickness of the bed sand layer, c e For the cross-section's sand-carrying capacity, c This represents the average volumetric sand content of the cross-section.

[0053] It should be noted that, in the embodiments of this application, oh Calculated by empirical formula, l This represents the ratio of near-bed sediment concentration to the cross-sectional average sediment concentration. When suspended sediment is dominant, it is taken as... l =1, when the transport phase is dominant, take l = h / h b The embodiments of this application calculate... oh , h b , c e The expression can be, but is not limited to: , , , in, d The particle size of the sediment n Let be the kinematic viscosity coefficient of water. c s The bulk density of silt. c For the specific gravity of water, For frictional flow velocity, = , s The effective specific gravity of sediment. s = r s / r w –1, q s This represents the sediment transport rate per unit width under saturated sediment transport conditions. The embodiments in this application use the Mayer-Peter formula for calculation. q s The expression can be, but is not limited to: , in, For Shields parameters, , i c The critical Shields parameter, i c = 0.04.

[0054] Optionally, in one embodiment of this application, a generalized geometric model of the river channel is used to generalize the river channel cross-section, so as to solve the continuous equation of the water-sediment mixture, the motion equation of the water-sediment mixture, the continuous equation of sediment, and the riverbed deformation equation simultaneously, so as to realize the coupled simulation of water and sediment transport, sediment scouring and deposition, and riverbed morphology evolution within the river network, and develop a river channel water and sediment morphology dynamic module, including: generalizing the river channel cross-sectional morphology based on the topographic data of key river channels; and constructing a coupled simulation strategy for one-dimensional river network water and sediment transport, sediment scouring and deposition, and riverbed deformation processes.

[0055] In the embodiments of this application, key river sections refer to sections that have a representative or controlling effect on river water and sediment movement and riverbed evolution (such as sections where the river width changes, tributary confluences, areas of dramatic scouring and deposition, and sections where hydrological observation stations are located). The topographic data of these sections can comprehensively reflect the main characteristics of the river channel and are the core basis for section generalization and model parameter calibration.

[0056] In addition, the coupled simulation strategy refers to a simulation method that incorporates multiple interrelated physical processes (such as water and sediment transport, sediment erosion and deposition, and riverbed deformation) into the same model framework, and reflects the interaction between processes (such as water flow velocity determining sediment transport capacity, and sediment erosion and deposition changing the bottom boundary of water flow through riverbed deformation, thereby affecting water flow) by solving the mathematical equations simultaneously.

[0057] In actual implementation, the embodiments of this application can simplify the complex natural river cross-section morphology based on the actual topographic data of key river sections and adopt a generalized geometric model of the river channel to reduce the complexity of subsequent numerical calculations. Then, based on the generalized river cross-section morphology, a coupled simulation strategy for the one-dimensional river network water and sediment transport, sediment scouring and deposition, and riverbed deformation processes is constructed. By simultaneously solving the water-sediment mixture continuity equation, water-sediment mixture motion equation, sediment continuity equation, and riverbed deformation equation, the linkage simulation of water and sediment transport, sediment scouring and deposition, and riverbed morphology changes within the river network is achieved.

[0058] The embodiments of this application can simplify the amount of calculation in complex terrain by generalizing the cross-sectional morphology of the river channel, thereby reducing the difficulty of practical application. At the same time, by constructing a coupled simulation strategy, it can ensure that the physical mechanisms of sediment erosion, siltation and morphological evolution in the river channel are closely matched, thereby enhancing the reliability of practical application.

[0059] Optionally, in one embodiment of this application, the generalization of river cross-sectional morphology based on key river cross-sectional topographic data includes: selecting key river cross-sections within the river network and extracting cross-sectional elevation data based on the key cross-sections; calculating the vertical distance from the lowest point of the cross-section to a preset reference water surface based on the cross-sectional elevation data, and increasing it step by step according to a preset increasing strategy to obtain the cross-sectional water-passing area under different water depth conditions; and obtaining the average cross-sectional width-water depth relationship curve of the river segment based on the cross-sectional water-passing area under different water depth conditions.

[0060] In the embodiments of this application, cross-sectional elevation data refers to the elevation of each sampling point measured after sampling points are set up at certain intervals along the transverse axis of the river cross section (a section perpendicular to the direction of water flow).

[0061] Furthermore, the preset reference water surface refers to a benchmark water level set according to the simulation target or actual needs, serving as a reference standard for calculating water depth and flow area. The specific preset reference water surface can be set by those skilled in the art based on actual conditions, and this application does not impose any specific limitations.

[0062] Furthermore, the preset increase strategy refers to the rule for gradually increasing the water level when calculating different water depths. This can cover the entire water depth range from the riverbed bottom to the preset reference water surface through orderly water level intervals. The specific preset increase strategy can be set by those skilled in the art according to actual conditions, and this application does not impose any specific limitations.

[0063] Furthermore, the cross-sectional area refers to the area of ​​a river channel that is occupied by water flow at a certain water level (i.e., the cross-sectional area below the water surface line), and it can measure the river's flow capacity. The larger the cross-sectional area, the more water the river can hold, and the stronger its flow capacity.

[0064] In some cases, embodiments of this application may select key river sections, extract section elevation data, and then, for each section, set a reference water level and calculate the vertical distance from the lowest point of the section elevation to the reference water level. D And sequentially change the position of the reference water surface from the lowest point of the cross-section elevation by a step size Δ D By gradually increasing the cross-sectional area, the water flow area under different water depth conditions can be obtained. A x .

[0065] Furthermore, embodiments of this application can utilize the data obtained from key cross-sections of all river channels within the research river network at different water depths. A x ( D The data points are summarized and plotted on a logarithmic coordinate system to fit the data points and obtain the average cross-sectional area-water depth curve of the river reach. The expression for the average cross-sectional area-water depth curve of the river reach can be, but is not limited to, as follows: , in, A The average cross-sectional area of ​​the water passage. D Because of the water depth, k A For scale parameters, α A These are morphological parameters.

[0066] Furthermore, in this embodiment, the average cross-sectional area-water depth relationship curve of the river segment can be differentiated to obtain the average cross-sectional width-water depth relationship curve of the river segment. The expression for the average cross-sectional width-water depth relationship curve of the river segment can be, but is not limited to, as follows: , in, B The average cross-sectional width of the river.

[0067] The embodiments of this application can generate the average cross-sectional width-depth relationship curve of the river section based on the key cross-section of the river, and convert discrete terrain data into quantitative parameters. At the same time, the cross-sectional water flow area under different water depth conditions can be gradually increased by a preset addition strategy, which can cover different hydrological scenarios and enhance practical application capabilities.

[0068] Optionally, in one embodiment of this application, the coupled simulation strategy includes at least one of the following: a water-sediment mixture continuity equation, a water-sediment mixture motion equation, a first sediment continuity equation, and a riverbed deformation equation, wherein the water-sediment mixture continuity equation is: , The equation of motion for the water-sediment mixture is: , The first sediment continuity equation is: , The equation for riverbed deformation is: , in, t For time, x For spatial coordinates, A The cross-sectional area of ​​the water passage. Q For cross-sectional flow, E For sediment uplift flux. D For settling flux, B The width of the cross section. p For the porosity of the bed sand, q l The unit width lateral inflow rate, g It is the acceleration due to gravity. z b For riverbed elevation, h Because of the water depth, t b For the bed surface shear stress, r The density of the water-sediment mixture. r s The density of sediment particles, r w The density is that of pure water. c This represents the cross-sectional average sediment volume concentration. h cThe water depth at the centroid of the cross-section. The density of the lateral incoming water flow. u l The lateral water flow velocity, s The sediment concentration in the lateral inflow water. A b This represents the cross-sectional area of ​​the riverbed.

[0069] It is understood that the embodiments of this application can construct a set of complementary equations through a coupled simulation strategy to describe the physical laws of water and sediment movement, sediment transport, and riverbed deformation, respectively. Then, by solving these equations simultaneously, the isolation between them is broken, and the interaction relationships are simulated. In the coupled simulation strategy, the water-sediment mixture continuity equation is based on the law of conservation of mass, describing the total mass balance of the water-sediment mixture; the water-sediment mixture motion equation is based on the law of conservation of momentum, describing the changes in the motion state of the water-sediment mixture; the first sediment continuity equation is based on the law of conservation of mass, describing the sediment transport balance; and the riverbed deformation equation is based on the law of conservation of mass, describing the evolution of the riverbed morphology.

[0070] The embodiments of this application can employ a coupled simulation strategy to solve multiple equations simultaneously, overcoming the limitations of uncoupled water-sediment models based on the assumption of weak alluvial rivers, which cannot reflect the interaction between water flow, sediment, and riverbed under strong unsteady flow conditions. By tracking water and sediment morphology over a long period, the long-term dynamic process of water and sediment morphology is simulated. At the same time, a complete logical chain of runoff and sediment production, water and sediment transport, and riverbed deformation is formed, which fits the physical mechanisms of sediment erosion, siltation, and morphological evolution in the river channel, thereby improving the ability to be applied in practice.

[0071] In step S102, the river channel water and sediment morphology dynamics module is coupled with the preset land surface hydrological model and the preset slope sediment erosion model to establish a land surface hydrology-slope erosion-river channel water and sediment morphology dynamics process model.

[0072] In the embodiments of this application, the preset land surface hydrological model can be understood as a model simulating the hydrological processes of the land surface (including elements such as vegetation, soil, and topography) to quantify the transformation relationships of precipitation, interception, infiltration, and runoff, providing a water source and dynamic basis for slope erosion and river hydrological processes. The specific settings of the preset land surface hydrological model can be configured by those skilled in the art according to actual conditions, and this application does not impose specific limitations.

[0073] Furthermore, the pre-defined slope sediment erosion model can be understood as a model that focuses on simulating sediment erosion processes at the slope scale. It uses physical or empirical equations to characterize processes such as raindrop splashing, slope runoff, and gully erosion, calculating the amount of sediment eroded per unit area of ​​the slope and the initial direction or rate of sediment transport. It serves as an intermediary link between land surface hydrology and river hydrology processes. The specific settings of the pre-defined slope sediment erosion model can be configured by those skilled in the art according to actual conditions; this application does not impose specific limitations.

[0074] In addition, the land surface hydrology-slope erosion-channel water and sediment morphology dynamic process model can be understood as a comprehensive watershed model coupled with the channel water and sediment morphology dynamic module, the preset land surface hydrology model, and the preset slope sediment erosion model. It covers the complete process of land surface runoff, slope erosion sediment production, channel water and sediment transport and riverbed evolution, and is used to realize the dynamic linkage simulation of water and sediment processes at different spatial scales (land surface, slope, channel).

[0075] In actual implementation, the embodiments of this application can couple the riverbed water and sediment morphology and dynamics module with the preset land surface hydrological model and the preset slope sediment erosion model to achieve the coordinated simulation of the three in the processes of runoff and sediment production, water and sediment transport and river evolution, so as to establish a land surface hydrology-slope erosion-riverbed water and sediment morphology and dynamics process model.

[0076] like Figure 3 As shown, in some cases, embodiments of this application can couple the riverbed water and sediment morphology dynamics module with a preset land surface hydrological model (such as the VIC-glacier model) and a preset slope sediment erosion model (such as the modified general soil loss equation MUSLE model) to form a land surface hydrology-slope erosion-riverbed water and sediment morphology dynamics process model. The preset land surface hydrological model, relying on driving data such as topographic data, near-surface meteorological data, vegetation cover data, glacier snow cover data, and soil data, simulates and generates rainfall runoff, snowmelt runoff, and glacier runoff, providing a hydrological and dynamic basis for slope sediment erosion. The preset slope sediment erosion model, using the slope runoff output by the preset land surface hydrological model as input, calculates the sediment erosion amount within the slope grid, characterizing the slope sediment erosion process. Then, through the sediment continuity equation and the kinematic wave approximation, it performs slope runoff calculations to simulate the transport process of water and sediment from the slope to the riverbed, and calculates the slope water and sediment runoff. The results, as lateral inflow and lateral sediment, are input into the riverbed water and sediment morphology dynamics module. Based on the generalized geometric model of the river, the module simultaneously establishes the continuity equation, motion equation, sediment continuity equation, and riverbed deformation equation for the water-sediment mixture. Following the river network topology, it adopts a step-by-step calculation method along the river segment, using upstream runoff and sediment transport as inflow conditions for downstream segments, and slope inflow and sediment transport as lateral input or boundary conditions to simulate the water and sediment morphology dynamics processes within the river network. Ultimately, it completes the coupled simulation of the entire chain of land surface hydrology, slope erosion, and riverbed water and sediment morphology dynamics.

[0077] Specifically, in one embodiment of this application, the riverbed water and sediment morphology dynamics module is coupled with a preset land surface hydrological model and a preset slope sediment erosion model to establish a land surface hydrology-slope erosion-riverbed water and sediment morphology dynamics process model, including: obtaining the runoff of the slope calculation grid; calculating the sediment erosion of the slope grid using the preset slope sediment erosion model based on the runoff; determining the confluence path from each slope grid to the river network based on the maximum slope of the slope grid and surrounding grids, and calculating the path length and slope; performing slope confluence calculation using the kinematic wave equation and the second sediment continuity equation to obtain the slope water and sediment confluence result; and using the slope water and sediment confluence result as lateral inflow and lateral sediment inflow to input the lateral inflow and lateral sediment inflow into the riverbed water and sediment morphology dynamics module.

[0078] In the embodiments of this application, the slope grid refers to discretizing the watershed slope area into several regular / irregular computational grids. Each grid independently performs runoff generation, erosion, and runoff calculations to conduct distributed simulations, which can improve the spatial resolution of water and sediment processes.

[0079] Furthermore, the confluence path refers to the specific route along which water and sediment move from the slope grid to the river network. Since water naturally flows in the direction of the steepest slope, the confluence path is determined by the direction of the steepest topographic slope. Its path length and slope are key parameters for calculating water flow velocity and transport time.

[0080] In addition, lateral inflow and lateral sediment refer to the water and sediment transported longitudinally relative to the upstream of the river channel. Water and sediment flowing in from the slopes on both sides of the river channel are considered lateral inputs, which affect the sediment transport capacity of the river channel and the evolution of the riverbed.

[0081] In actual implementation, the embodiments of this application can perform watershed hydrological process calculations to obtain the runoff of the slope calculation grid. Based on the runoff of the slope calculation grid, a preset slope sediment erosion model is applied to calculate the sediment erosion within the slope grid. Then, based on the maximum slope of the slope grid and the surrounding grids, the confluence path from each slope grid to the river network is determined. The length and slope of the confluence path of each slope grid are calculated. Subsequently, the kinematic wave equation and the sediment continuity equation are applied to perform slope confluence calculations to obtain the slope water and sediment confluence results. The slope water and sediment confluence results are then used as lateral inflow and lateral sediment input into the river water and sediment morphology dynamics module to simulate the river water and sediment morphology dynamics process, thereby establishing a land surface hydrology-slope erosion-river water and sediment morphology dynamics process model.

[0082] The embodiments of this application can reconstruct the physical processes of runoff and sediment generation, water and sediment transport and collection in a watershed by observing the processes of slope runoff generation, slope erosion, slope confluence and lateral input from the river channel. It can reflect the relationship between slope erosion and river siltation or scouring, adapt to complex terrain and climatic conditions, and improve the applicability of practical applications.

[0083] Optionally, in one embodiment of this application, the motion wave equation and the second sediment continuity equation are respectively: , , , in, n The roughness coefficient is Manning's coefficient. R For hydraulic radius, S 0 represents the surface slope of the grid cell. R runoff This refers to the surface runoff within the grid calculated by the land surface hydrological model. R sed The amount of sediment produced within the grid calculated by the slope erosion model.

[0084] In some cases, embodiments of this application can couple the kinematic wave equation with the second sediment continuity equation, using the surface runoff of the land surface hydrological model and the sediment yield within the grid of the slope erosion model as source terms to simulate water and sediment transport at the slope scale, perform slope runoff calculations, and obtain slope water and sediment runoff results.

[0085] The embodiments of this application can use the kinematic wave equation and the second sediment continuity equation to calculate the slope confluence. On the one hand, the equations can simplify the calculation and improve the efficiency of slope water and sediment transport simulation. On the other hand, they can reflect the dynamic relationship between water flow and sediment, ensuring the continuity of the whole chain simulation of the land surface, slope, and river water and sediment morphology and dynamic processes, taking into account both efficiency and practicality.

[0086] In step S103, the model is calibrated and validated based on the land surface hydrology-slope erosion-channel water and sediment morphological dynamic process model using measured flow and sediment flux.

[0087] In practical implementation, the embodiments of this application can use measured flow and sediment flux to calibrate and verify the model based on the land surface hydrology-slope erosion-channel water and sediment morphological dynamic process model. Model calibration can be understood as adjusting key parameters in the model (such as runoff generation and infiltration parameters, soil erodibility parameters, channel roughness, and sediment transport parameters) to make the simulated flow and sediment flux of the model closely match the measured flow and sediment flux, thereby calibrating the model's accuracy. Model verification can be understood as using independent measured flow and sediment flux to verify the accuracy of the calibrated model under different hydrological scenarios (such as high-water season and low-water season), ensuring that the model can stably reflect the true physical laws of watershed water and sediment processes.

[0088] For example, embodiments of this application can collect geographic data and hydrological and meteorological information of the Tuotuo River Basin, including but not limited to elevation, vegetation cover type, soil texture, precipitation, wind speed at 2 m near the ground, maximum temperature, minimum temperature, flow rate, and sediment transport rate. The meteorological data is then used as a driving force for the model to construct a land surface hydrological-slope erosion-channel water and sediment morphological dynamic model of the Tuotuo River Basin. It should be noted that the spatial accuracy of the slope calculation grid is 3 km, and the spatial accuracy of the river network calculation grid is 2 km.

[0089] Furthermore, in this embodiment of the application, the parameter ranges for the land surface hydrological model and the slope erosion model can be determined based on research data, and parameter calibration methods can be used to determine the parameter values. The data for parameter calibration and model validation come from the measured flow and sediment flux of the Tuotuohe Hydrological Station from 1985 to 2004 and from 2005 to 2018. Figure 4 As shown, (ab) represents the simulated flow rate, and (cd) represents the simulated sediment flux. Figure 3 In the land surface hydrology-slope erosion-channel water and sediment dynamics model of the Tuotuo River Basin, the Nash efficiency coefficient (NSE) for simulated flow exceeds 0.85, the Pearson correlation coefficient (R) exceeds 0.94, and the root mean square error (RMSE) is less than 26 m. 3 / s; the simulated sediment flux has an NSE exceeding 0.78, an R value exceeding 0.89, and an RMSE less than 50 kg / s. The expressions for calculating NSE, R, and RMSE can be, but are not limited to, as follows: , , , in, O i For observations of flow rate or sediment flux, E i These are simulated values ​​for flow rate or sediment flux. and These are the observed and simulated average flow rates and sediment fluxes, respectively. N This represents the total number of data points.

[0090] The embodiments of this application can use measured flow rate and sediment flux to calibrate and verify the model, reduce the deviation between simulation results and actual results, improve the accuracy of the model, and enhance its application value.

[0091] In step S104, after verification, the elevation, soil texture, vegetation cover type and meteorological data are input for the watershed as the object, so as to use the land surface hydrology-slope erosion-channel water and sediment morphological dynamic process model to simulate the watershed-scale hydrological process, slope erosion process and channel water and sediment morphological dynamic process.

[0092] In the embodiments of this application, the hydrological process can be understood as the hydrological cycle process of the land surface of the watershed, including precipitation interception, soil infiltration, surface runoff, groundwater runoff, evapotranspiration, etc.; the slope erosion process can be understood as the process of soil particles being stripped and transported under the influence of rainfall and runoff at the slope scale; the river channel water and sediment morphological dynamic process can be understood as the process in which water flow drives sediment transport, sediment erosion and deposition change the riverbed morphology, and the riverbed morphology in turn affects the water flow velocity and flow capacity.

[0093] In actual implementation, the embodiments of this application can take the watershed as the research object, and input factors such as elevation reflecting topographic features, soil texture reflecting soil erodibility, vegetation cover type reflecting evapotranspiration characteristics, and meteorological data reflecting precipitation and temperature. Relying on the land surface hydrology-slope erosion-channel water and sediment morphological dynamic process model, the entire chain of watershed-scale hydrological processes, slope erosion processes, and channel water and sediment morphological dynamic processes can be simulated through multi-module coupling and physical mechanism driving.

[0094] For example, such as Figure 5 As shown, the hydrodynamic processes of key sections of the river network within the simulated area are illustrated. (a) shows the section location; (bc) shows the simulated flow and sediment flux changes in the main channel during the flood season of June to September 2004, and the observed flow and sediment flux changes at the Tuotuohe station, respectively; and (d) shows the riverbed deformation that occurred in the main channel from 1985 to 2018. The observed hydrodynamic processes at the Tuotuohe station are largely consistent with the simulated values, confirming the reliability of the land surface hydrology-slope erosion-channel hydrodynamic process model. Compared with watershed hydrodynamic models that directly apply empirical formulas to estimate channel erosion and deposition while neglecting channel morphology changes, the land surface hydrology-slope erosion-channel hydrodynamic process model proposed in this application can simulate the riverbed deformation process through a coupled simulation strategy based on physical mechanisms.

[0095] The following section describes the numerical simulation method for distributed watershed water and sediment morphological dynamic processes proposed in this application, using a specific embodiment as an example.

[0096] In this application embodiment, a preset land surface hydrological model and a preset slope erosion model can be selected to develop a river channel water and sediment morphology dynamic module. The control equation set consisting of the water and sediment mixture continuity equation, the water and sediment mixture motion equation, the first sediment continuity equation, and the riverbed deformation equation is combined with the slope runoff and slope erosion results to calculate the river channel water and sediment transport.

[0097] Subsequently, this embodiment couples the riverbed water and sediment morphology dynamics module with a preset land surface hydrological model and a preset slope erosion model. Specifically, this embodiment transfers the runoff simulated by the preset land surface hydrological model to the preset slope erosion model. Based on the runoff of the slope calculation grid, the sediment erosion within the grid is calculated. Then, the kinematic wave equation and the second sediment continuity equation are applied to calculate the water and sediment transport on the slope surface. Subsequently, the riverbed water and sediment morphology dynamics module is applied to calculate the water and sediment movement within the river network, using a step-by-step calculation method along the river segment, following the river network topology. The runoff and sediment transport of the upstream river segment serve as the inflow conditions for the downstream river segment: at the confluence of river segments, the runoff and sediment transport fluxes from multiple tributaries are directly added to form the total inflow of the downstream river segment; for river segments without upstream water, slope runoff and slope sediment production are used as boundary conditions; for river segments with upstream water, slope water and sediment transport are used as the input models for lateral inflow and lateral sediment transport.

[0098] Furthermore, the embodiments of this application can collect geographical data and hydrological and meteorological data of the watershed, including but not limited to elevation, vegetation cover type, soil texture, precipitation, wind speed at 2 m near the ground, maximum temperature, minimum temperature, flow rate, and sediment transport rate. Then, the meteorological data is used as the forced driver of the model to construct a land surface hydrology-slope erosion-channel water and sediment morphological dynamic model of the watershed. Then, the parameter value range of the preset land surface hydrology model and the preset slope erosion model can be determined according to the research data, and the parameter values ​​can be determined by the parameter calibration method. Thus, based on the measured data and simulation requirements of the study area, the required data and parameter values ​​of the model are input to run the model to simulate the hydrological process, slope erosion process and channel water and sediment morphological dynamic process within the watershed.

[0099] The distributed watershed water and sediment morphological dynamics numerical simulation method proposed in this application can generalize the river cross-section using a generalized geometric model to simultaneously solve the water-sediment mixture continuity equation, water-sediment mixture motion equation, sediment continuity equation, and riverbed deformation equation, thus developing a water and sediment morphological dynamics module. This module is then coupled with a pre-set land surface hydrological model and a pre-set slope sediment erosion model to establish a land surface hydrological-slope erosion-watershed water and sediment morphological dynamics process model. The model is then calibrated and validated using measured flow and sediment flux, thereby simulating watershed-scale hydrological processes, slope erosion processes, and watershed water and sediment morphological dynamics. This method achieves numerical simulation of distributed watershed water and sediment dynamics processes, closely reflecting the physical mechanisms of sediment erosion, deposition, and morphological evolution within the river channel. It also utilizes a generalized geometric model to adapt to complex river morphologies and simplifies the calculation process on the slope using motion wave equations and a second sediment continuity equation, meeting the computational needs of long-term, large-scale watershed operations while maintaining both efficiency and practicality. This solves the problem that related technologies, in order to fit the physical mechanisms of sediment erosion, deposition, and morphological evolution in river channels, require a huge amount of computation, making them difficult to adapt to the computational needs of long periods and large watersheds, thus limiting their practical applications.

[0100] Next, referring to the accompanying drawings, a numerical simulation device for distributed watershed water and sediment morphological dynamic processes proposed according to an embodiment of this application is described.

[0101] Figure 6 This is a block diagram of a distributed watershed water and sediment morphological dynamics numerical simulation device provided according to an embodiment of this application.

[0102] like Figure 6 As shown, the distributed watershed water and sediment morphological dynamic process numerical simulation device 60 includes: development module 100, establishment module 200, verification module 300 and simulation module 400.

[0103] Among them, the development module 100 is used to generalize the river cross section using a generalized geometric model of the river channel, so as to solve the continuous equation of the water-sediment mixture, the motion equation of the water-sediment mixture, the continuous equation of sediment and the riverbed deformation equation simultaneously, so as to realize the coupled simulation of water and sediment transport, sediment scouring and deposition and riverbed morphology evolution within the river network, and develop the river channel water and sediment morphology dynamic module.

[0104] Module 200 is established to couple the river channel water and sediment morphology dynamics module with a preset land surface hydrological model and a preset slope sediment erosion model to establish a land surface hydrology-slope erosion-river channel water and sediment morphology dynamics process model.

[0105] The verification module 300 is used to calibrate and verify the model based on the land surface hydrology-slope erosion-channel water and sediment morphological dynamic process model using measured flow and sediment flux.

[0106] The simulation module 400 is used, after verification, to simulate the hydrological processes, slope erosion processes and river water and sediment morphodynamic processes at the watershed scale by inputting elevation, soil texture, vegetation cover type and meteorological data, with the watershed as the object.

[0107] Optionally, in one embodiment of this application, the development module 100 includes a generation unit and a construction unit.

[0108] The generation unit is used to generalize the cross-sectional morphology of the river channel based on the topographic data of key river sections.

[0109] The building blocks are used to construct coupled simulation strategies for one-dimensional river network processes such as water and sediment transport, sediment erosion and deposition, and riverbed deformation.

[0110] Optionally, in one embodiment of this application, the generation unit includes: a first generation subunit, a second generation subunit, and a third generation subunit.

[0111] The first generation sub-unit is used to select key river sections within the river network and extract section elevation data based on the key sections.

[0112] The second generation subunit is used to calculate the vertical distance from the lowest point of the cross section to the preset reference water surface based on the cross section elevation data, and to increase it step by step according to the preset increasing strategy to obtain the cross section water passage area under different water depth conditions.

[0113] The third generation sub-unit is used to obtain the average cross-sectional width-water depth relationship curve of the river section based on the cross-sectional water flow area under the different water depth conditions.

[0114] Optionally, in one embodiment of this application, the coupled simulation strategy includes at least one of the following: a water-sediment mixture continuity equation, a water-sediment mixture motion equation, a first sediment continuity equation, and a riverbed deformation equation, wherein the water-sediment mixture continuity equation is: , The equation of motion for the water-sediment mixture is: , The first sediment continuity equation is: , The equation for riverbed deformation is: , in, t For time, x For spatial coordinates, A The cross-sectional area of ​​the water passage.Q For cross-sectional flow, E For sediment uplift flux. D For settling flux, B The width of the cross section. p For the porosity of the bed sand, q l The unit width lateral inflow rate, g It is the acceleration due to gravity. z b For riverbed elevation, h Because of the water depth, t b For the bed surface shear stress, r The density of the water-sediment mixture. r s The density of sediment particles, r w The density is that of pure water. c This represents the cross-sectional average sediment volume concentration. h c The water depth at the centroid of the cross-section. The density of the lateral incoming water flow. u l The lateral water flow velocity, s The sediment concentration in the lateral inflow water. A b This represents the cross-sectional area of ​​the riverbed.

[0115] Optionally, in one embodiment of this application, the establishment module 200 includes: a first calculation unit, a second calculation unit, a third calculation unit, a fourth calculation unit, and an input unit.

[0116] The first calculation unit is used to obtain the flow rate of the slope calculation grid.

[0117] The second calculation unit is used to calculate the amount of sediment erosion of the slope grid based on the flow rate and using the preset slope sediment erosion model.

[0118] The third calculation unit is used to determine the confluence path from each slope grid to the river network based on the maximum slope of the slope grid and the surrounding grid, and to calculate the path length and slope.

[0119] The fourth calculation unit is used to perform slope runoff calculations using the motion wave equation and the second sediment continuity equation to obtain the slope water and sediment runoff results.

[0120] The input unit is used to take the slope water and sediment confluence results as lateral inflow and lateral sediment, and input the lateral inflow and lateral sediment into the river channel water and sediment morphology dynamic module.

[0121] Optionally, in one embodiment of this application, the motion wave equation and the second sediment continuity equation are respectively: , , , in, n The roughness coefficient is Manning's coefficient. R For hydraulic radius, S 0 represents the surface slope of the grid cell. R runoff This refers to the surface runoff within the grid calculated by the land surface hydrological model. R sed The amount of sediment produced within the grid calculated by the slope erosion model.

[0122] It should be noted that the foregoing explanation of the numerical simulation method for distributed watershed water and sediment morphology and dynamic processes also applies to the numerical simulation device for distributed watershed water and sediment morphology and dynamic processes in this embodiment, and will not be repeated here.

[0123] The distributed watershed water and sediment morphological dynamics numerical simulation device proposed in this application can generalize the river cross-section using a generalized geometric model to simultaneously solve the water-sediment mixture continuity equation, water-sediment mixture motion equation, sediment continuity equation, and riverbed deformation equation, thus developing a water and sediment morphological dynamics module. This module is then coupled with a pre-set land surface hydrological model and a pre-set slope sediment erosion model to establish a land surface hydrology-slope erosion-watershed water and sediment morphological dynamics process model. The model is then calibrated and verified using measured flow and sediment flux. This allows the model to simulate watershed-scale hydrological processes, slope erosion processes, and watershed water and sediment morphological dynamics, achieving numerical simulation of distributed watershed water and sediment dynamics processes. This approach not only conforms to the physical mechanisms of sediment erosion, deposition, and morphological evolution within the river channel but also utilizes a generalized geometric model to adapt to complex river morphologies. On the slope, it simplifies the calculation process by employing motion wave equations and a second sediment continuity equation, adapting to the computational needs of long-term, large-scale watershed operations while maintaining both efficiency and practicality. This solves the problem that related technologies, in order to fit the physical mechanisms of sediment erosion, deposition, and morphological evolution in river channels, require a huge amount of computation, making them difficult to adapt to the computational needs of long periods and large watersheds, thus limiting their practical applications.

[0124] Figure 7 This is a schematic diagram of the structure of an electronic device provided according to an embodiment of this application. The electronic device may include: The memory 701, the processor 702, and the computer program stored on the memory 701 and executable on the processor 702.

[0125] When the processor 702 executes the program, it implements the numerical simulation method for distributed watershed water and sediment morphological dynamic processes provided in the above embodiments.

[0126] Furthermore, electronic devices also include: Communication interface 703 is used for communication between memory 701 and processor 702.

[0127] The memory 701 is used to store computer programs that can run on the processor 702.

[0128] The memory 701 may include high-speed RAM memory, and may also include non-volatile memory, such as at least one disk storage device.

[0129] If the memory 701, processor 702, and communication interface 703 are implemented independently, then the communication interface 703, memory 701, and processor 702 can be interconnected via a bus to complete communication between them. The bus can be an Industry Standard Architecture (ISA) bus, a Peripheral Component Interconnect (PCI) bus, or an Extended Industry Standard Architecture (EISA) bus, etc. Buses can be categorized into address buses, data buses, control buses, etc. For ease of representation, Figure 7 The bus is represented by a single thick line, but this does not mean that there is only one bus or one type of bus.

[0130] Optionally, in a specific implementation, if the memory 701, processor 702, and communication interface 703 are integrated on a single chip, then the memory 701, processor 702, and communication interface 703 can communicate with each other through an internal interface.

[0131] The processor 702 may be a central processing unit (CPU), an application specific integrated circuit (ASIC), or one or more integrated circuits configured to implement the embodiments of this application.

[0132] This application also provides a computer-readable storage medium storing a computer program that, when executed by a processor, implements the above-described numerical simulation method for distributed watershed water and sediment morphological dynamic processes.

[0133] This application also provides a computer program product, including a computer program that, when executed, implements the above-described distributed watershed water and sediment morphological dynamic process numerical simulation method.

[0134] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0135] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this application, "N" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0136] Any process or method described in the flowchart or otherwise herein can be understood as representing a module, segment, or portion of code comprising one or N executable instructions for implementing custom logic functions or processes, and the scope of the preferred embodiments of this application includes additional implementations in which functions may be performed not in the order shown or discussed, including substantially simultaneously or in reverse order depending on the functions involved, as should be understood by those skilled in the art to which embodiments of this application pertain.

[0137] The logic and / or steps represented in the flowchart or otherwise described herein, for example, can be considered as a sequenced list of executable instructions for implementing logical functions, and can be embodied in any computer-readable medium for use by, or in conjunction with, an instruction execution system, apparatus, or device (such as a computer-based system, a processor-included system, or other system that can fetch and execute instructions from, an instruction execution system, apparatus, or device). For the purposes of this specification, "computer-readable medium" can be any means that can contain, store, communicate, propagate, or transmit programs for use by, or in conjunction with, an instruction execution system, apparatus, or device. More specific examples (a non-exhaustive list) of computer-readable media include: an electrical connection having one or more wires (electronic device), a portable computer disk drive (magnetic device), random access memory (RAM), read-only memory (ROM), erasable and editable read-only memory (EPROM or flash memory), fiber optic devices, and portable optical disc read-only memory (CDROM). Alternatively, the computer-readable medium may be paper or other suitable media on which the program can be printed, since the program can be obtained electronically by optically scanning the paper or other medium, followed by editing, interpreting, or otherwise processing as necessary, and then stored in a computer memory.

[0138] It should be understood that the various parts of this application can be implemented using hardware, software, firmware, or a combination thereof. In the above embodiments, the N steps or methods can be implemented using software or firmware stored in memory and executed by a suitable instruction execution system. If implemented in hardware, as in another embodiment, it can be implemented using any one or more of the following techniques known in the art: discrete logic circuits having logic gates for implementing logical functions on data signals, application-specific integrated circuits (ASICs) having suitable combinational logic gates, programmable gate arrays (PGAs), field-programmable gate arrays (FPGAs), etc.

[0139] Those skilled in the art will understand that all or part of the steps of the methods in the above embodiments can be implemented by a program instructing related hardware. The program can be stored in a computer-readable storage medium, and when executed, the program includes one or a combination of the steps of the method embodiments.

[0140] Furthermore, the functional units in the various embodiments of this application can be integrated into a processing module, or each unit can exist physically separately, or two or more units can be integrated into a module. The integrated module can be implemented in hardware or as a software functional module. If the integrated module is implemented as a software functional module and sold or used as an independent product, it can also be stored in a computer-readable storage medium.

[0141] The storage medium mentioned above can be a read-only memory, a disk, or an optical disk, etc. Although embodiments of this application have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting this application. Those skilled in the art can make changes, modifications, substitutions, and variations to the above embodiments within the scope of this application.

Claims

1. A numerical simulation method for distributed watershed water and sediment morphological dynamic processes, characterized in that, Includes the following steps: The generalized geometric model of the river channel is used to generalize the river channel cross section, and the continuous equation of the water-sediment mixture, the motion equation of the water-sediment mixture, the sediment continuity equation and the riverbed deformation equation are solved simultaneously to realize the coupled simulation of water and sediment transport, sediment scouring and deposition and riverbed morphology evolution in the river network, and to develop a river channel water and sediment morphology dynamic module. The riverbed water and sediment morphology dynamics module is coupled with a preset land surface hydrological model and a preset slope sediment erosion model to establish a land surface hydrology-slope erosion-riverbed water and sediment morphology dynamics process model. Based on the land surface hydrology-slope erosion-channel water and sediment morphological dynamic process model, the model was calibrated and verified using measured flow and sediment flux. After successful verification, the elevation, soil texture, vegetation cover type and meteorological data are input for the watershed as the object, so as to use the land surface hydrology-slope erosion-channel water and sediment morphodynamic process model to simulate the watershed-scale hydrological process, slope erosion process and channel water and sediment morphodynamic process.

2. The method according to claim 1, characterized in that, The method employs a generalized geometric model to generalize the river cross-section, enabling the simultaneous solution of the continuity equation of the water-sediment mixture, the motion equation of the water-sediment mixture, the sediment continuity equation, and the riverbed deformation equation. This achieves coupled simulation of water and sediment transport, sediment erosion and deposition, and riverbed morphology evolution within the river network. A river water-sediment morphology dynamic module is developed, including: The cross-sectional morphology of the river channel is generalized based on topographic data of key river sections. A coupled simulation strategy for one-dimensional river network processes involving water and sediment transport, sediment erosion and deposition, and riverbed deformation was developed.

3. The method according to claim 2, characterized in that, The generalization of river cross-sectional morphology based on key river section topographic data includes: Select key cross-sections of the river channels within the river network, and extract cross-section elevation data based on the key cross-sections; The vertical distance from the lowest point of the cross section to the preset reference water surface is calculated based on the cross section elevation data, and then gradually increased according to the preset increasing strategy to obtain the cross section water passage area under different water depth conditions. The average cross-sectional width-water depth relationship curve of the river section is obtained based on the cross-sectional water area under different water depth conditions.

4. The method according to claim 2, characterized in that, The coupled simulation strategy includes at least one of the following: the water-sediment mixture continuity equation, the water-sediment mixture motion equation, the first sediment continuity equation, and the riverbed deformation equation, wherein... The continuity equation for the water-sediment mixture is: ， The equation of motion for the water-sediment mixture is: ， The first sediment continuity equation is: ， The equation for riverbed deformation is: ， in, t For time, x For spatial coordinates, A The cross-sectional area of ​​the water passage. Q For cross-sectional flow, E For sediment uplift flux. D For settling flux, B The width of the cross section. p For the porosity of the bed sand, q l The unit width lateral inflow rate, g It is the acceleration due to gravity. z b For riverbed elevation, h Because of the water depth, τ b For the bed surface shear stress, ρ The density of the water-sediment mixture. ρ s The density of sediment particles, ρ w The density is that of pure water. c This represents the cross-sectional average sediment volume concentration. h c The water depth at the centroid of the cross-section. The density of the water flowing laterally. u l The lateral water flow velocity, s The sediment concentration in the lateral inflow water. A b This represents the cross-sectional area of ​​the riverbed.

5. The method according to claim 4, characterized in that, The coupling of the riverbed water and sediment morphology dynamics module with a preset land surface hydrological model and a preset slope sediment erosion model to establish a land surface hydrology-slope erosion-riverbed water and sediment morphology dynamics process model includes: Obtain the flow rate of the slope computational grid; Based on the production flow, the sediment erosion amount of the slope grid is calculated using the preset slope sediment erosion model; The confluence path from each slope grid to the river network is determined based on the maximum slope of the slope grid and the surrounding grid, and the path length and slope are calculated. The slope runoff calculation was performed using the kinematic wave equation and the second sediment continuity equation to obtain the slope water and sediment runoff results; The slope water and sediment confluence results are used as lateral inflow and lateral sediment, and the lateral inflow and lateral sediment are input into the river channel water and sediment morphology dynamic module.

6. The method according to claim 5, characterized in that, The motion wave equation and the second sediment continuity equation are respectively: ， ， ， in, n The roughness coefficient is Manning's coefficient. R For hydraulic radius, S 0 represents the surface slope of the grid cell. R runoff This refers to the surface runoff within the grid calculated by the land surface hydrological model. R sed The amount of sediment produced within the grid calculated by the slope erosion model.

7. A distributed numerical simulation device for water and sediment morphological dynamic processes in a watershed, characterized in that, Includes the following steps: The development module is used to generalize the river cross section using a generalized geometric model of the river channel, so as to solve the continuous equation of the water-sediment mixture, the motion equation of the water-sediment mixture, the continuous equation of sediment and the riverbed deformation equation simultaneously, so as to realize the coupled simulation of water and sediment transport, sediment scouring and deposition and riverbed morphology evolution within the river network, and to develop the river channel water and sediment morphology dynamic module. A module is established to couple the river channel water and sediment morphology and dynamics module with a preset land surface hydrological model and a preset slope sediment erosion model to establish a land surface hydrology-slope erosion-river channel water and sediment morphology and dynamics process model. The verification module is used to calibrate and verify the model based on the land surface hydrology-slope erosion-channel water and sediment morphological dynamic process model using measured flow and sediment flux. The simulation module, after successful verification, is used to simulate watershed-scale hydrological processes, slope erosion processes, and riverbed water and sediment morphodynamic processes by inputting elevation, soil texture, vegetation cover type, and meteorological data, with the land surface hydrology-slope erosion-channel water and sediment morphodynamic process model.

8. An electronic device, characterized in that, include: A memory, a processor, and a computer program stored in the memory and executable on the processor, the processor executing the program to implement the distributed watershed water and sediment morphological dynamic process numerical simulation method as described in any one of claims 1-6.

9. A computer-readable storage medium having a computer program stored thereon, characterized in that, The program is executed by the processor to implement the distributed watershed water and sediment morphological dynamic process numerical simulation method as described in any one of claims 1-6.

10. A computer program product, comprising a computer program, characterized in that, The computer program is executed to implement the numerical simulation method for distributed watershed water and sediment morphological dynamic processes as described in any one of claims 1-6.

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